DEVELOPMENT OF ENZYME CONDUCTOMETRIC BIOSENSOR FOR DOPAMINE DETERMINATION IN AQUEOUS SAMPLES

Abstract

In this work, a conductometric biosensor was developed to determine dopamine concentrations. To create a bioselective element of the biosensor we used the enzyme laccase, which was immobilized on the surface of the physical transducer by covalent crosslinking of glutaraldehyde with bovine serum albumin. Two pairs of gold interdigitated electrodes deposited on a sital substrate were used as a conductometric transducer. The optimal conditions of laccase immobilization were selected. The influence of solution parameters (ionic strength, pH, buffer capacity) on the work of the developed biosensor for dopamine determination was investigated. The biosensors demonstrated high sensitivity to dopamine (minimum limit of detection 5 μM). The linear range of analyte determination was up to 1 mM. It was established that the developed biosensor is characterized by high reproducibility of responses during several hours of continuous operation (RSD = 10%). The proposed biosensor was tested regarding the possibility of its long-term storage under different conditions. It was shown that dopamine-sensitive biosensor was characterized by good selectivity towards probable interferents and can be further used to determine the concentration of dopamine in biological and pharmaceutical